Regarding content, I think you're going to start seeing 4K/8K content offered by folks such as Netflix, etc, and other streaming services, more readily than before. (You're also going to be able to download it to your tablet or mobile device and plug it directly into your 8K TV. Trust me, I work in the chip industry that makes this stuff.)
The makers of these UHD systems know people aren't going to upgrade until there's a reason to (i.e., sufficient content). Because we live in a slightly different age however, I think you'll see it rolled out faster than HD content was for HD systems.